invoice

name	invoice
description	Issue and collect customer invoices (accounts receivable) and enter and pay vendor bills (accounts payable), each posting the correct double-entry. Use when the user asks to invoice a customer, record a payment received, enter a vendor bill, pay a bill, or check who owes them / what they owe. Ties each invoice/bill to a CRM company or contact.

Invoicing (AR / AP)

Customer invoices (accounts receivable) and vendor bills (accounts payable) each post a balanced journal entry and create an ar-invoice / ap-bill document tied to the CRM counterparty. The four actions and their postings (canonical source: the engine's posting builders in hq-pro/src/ontology/accounting/posting.ts):

Action	Debit	Credit	Document
Issue customer invoice	Accounts Receivable	Income	ar-invoice (open)
Receive customer payment	Cash / bank	Accounts Receivable	ar-invoice → paid
Enter vendor bill	Expense (or Asset)	Accounts Payable	ap-bill (open)
Pay vendor bill	Accounts Payable	Cash / bank	ap-bill → paid

Posting an invoice/bill

1. Resolve the counterparty in the CRM first. The customer/vendor is a CRM company (or contact) — find it with the /crm skill and use its entity path as counterpartyRef. A single client record then spans pipeline → contract → billing → ledger.
2. Write two entities (local-first, then /hq-sync for the company):
   • a journal-entry with the balanced lines from the table above, and
   • an ar-invoice / ap-bill with counterpartyRef, amountDue, invoiceStatus, issueDate, optional dueDate, and postedEntryRef (the journal entry's id). Link them: the journal entry "Posts" the document; the document is "Posted by" the entry. Entity ids are deterministic (sha256("ar-invoice:AR Invoice <number>"), etc.), so re-running is idempotent.
3. Write the journal entry LAST. The ledger only reflects posted entries, so ordering the authoritative entry last means a crash mid-write leaves the books unchanged and the action safely re-runnable.

Payments don't edit — they reverse/append

Receiving a payment or paying a bill is a new journal entry, plus a re-emit of the same invoice/bill document (same id) with invoiceStatus: "paid" and amountDue: 0. Never edit the original issue entry — that preserves the audit trail. (To void or correct an issued invoice, post a reversing entry per the double-entry-rules knowledge, don't mutate it.)

Reading AR/AP

Outstanding receivables/payables fall out of the account balances in accounting-projection.json (see the run-reports skill): the Accounts Receivable balance is what customers owe you; Accounts Payable is what you owe vendors. Per-invoice status lives on the ar-invoice / ap-bill documents (open vs paid).

Integrity

Every posting balances by construction (equal debit and credit). The engine rejects any unbalanced entry, so if a posting won't balance, the inputs are wrong — fix them rather than forcing it.